We get this warning because the hostname of the box is hostname.servers.domain.edu but the MX record is mail.domain.edu. The check seems to be making sure that the hostname and MX record match, and when they don't it gives you this message. We always just enter "no" to keep it the way we told it, and it works for us.

First of all what DNS server are you using? BIND?
If so your PTR zone is completely wrong. Your "forward" zone file also has a few problems that are causing errors. Another thing... the filename itself is important in BIND so I am only guessing at the file names you have (What I am showing below is what they should be if not). Try changing them to something like these: